Influence of Stage of Cycle, Progestagen Treatment and Dose of Oestrogen on Uterine Motility in the Ewe

Low fertility in ewes after control of oestrus with progestagens has been attributed to abnormal transport and/or reduced viability of spermatozoa in the female tract (Quinlivan & Robinson, 1967, 1969). Smith & Allison (1971) have shown an effect of progestagen treatment on the quantity of cervical mucus produced at the subsequent oestrus and have suggested that this prevents the establishment of a normal population of spermatozoa in the cervix. Another factor contributing to transport of spermatozoa is uterine motility (Mattner, 1963; Mattner & Braden, 1963; Lightfoot & Restall, 1971). Differences in uterine motility at oestrus and mid-cycle have been reported by Polovceva (1940) and Mann (1969) and they suggested that uterine motility was affected by ovarian hormones. It is therefore likely that manipulation of the oestrous cycle by use of progestagens and the associated